Wifi Robot : a hacked WRT54GL rover

[Jon Bennett] sent us this link to his Wifi Robot. After playing with a Linksys WRT54GL router, he was inspired to build something that would utilize this embedded Linux system. Using a thrift store R/C truck, he built a wireless robot rover. This thing can be controlled over the internet, or by laptop with a range of about 500 meters.

The router has been modified to have 2 Serial ports and a 1GB SD Card. It connects to a micro controller, which could be an Arduino or AVR Butterfly. He has supplied information for both. The truck has been mostly gutted, leaving only the chassis and electronics. He had to beef up some of the truck electronics when they fried under the load. The entire unit is powered by a pair of 7.2 Volt 3800 mAh battery packs. The most important thing on the list though, is the horn. You can honk the horn while you are driving this thing around.

The site supplies tons of information including pictures of his build, videos of it in action, speed tests, schematics, software downloads, and resource links. Great job [Jon].

Pretty impressive project … but I can’t shake the thought that he basically took the simple, low-power, lightweight RC interface that the car already had and bolted on a heavy, power-hungry, overly complex RC interface in its place. Didn’t “hacking” used to mean finding elegant technical solutions to problems? Nowadays it seems like it just means forcing COTS stuff to do something neat.

It means both now a days… I know a guy that has an evdo modem in his wrt. With that, and this, you could go pretty much as far as the battery would allow. I haven’t hit the web page yet, but he’s probably still using stock antennas as well. Throw a couple 7Dbi antennas on there and the range should improve.

GPS interfaced with Google Maps would be an excellent addition to this project. And when the power is too low it pops open an umbrella that covers the whole car so it looks like a piece of fabric lying on the ground – waiting for the driver to pick it up.

Ken – I agree with your general sense that a lot that goes by the name of “hacking” these days isn’t all that impressive.

But I don’t think this falls into that catagory. It is true that if all the guy does is do the same commands as would be done via a joy stick, through a laptop, then it is kind of pointless.

But this project gives you a lot more than an internet capable joystick. The robot can potentially be autonomous, which is a huge leap in capability. The robot can now have sensors also integrated into the router, and you can write programs to control the robot without knowing special microcontroller code, but using C on Linux.

The alternatives that would get you to the same place (using C on Linux to control a robot) are all much more expensive. There are kits that use a laptop as the controller, and some of those tiny solid state computers might replace the laptop, but you are going to spend hundreds of dollars. This gets you there for something around a hundred, presuming you get everything used.

I have to agree with this being a ‘hack,’ especially since it /can/ be used to solve problems. Use that 1GB of space with that camera and some logic and you have a roaming security camera. Top it off with some sensors and you can have it find a ‘dock’ when it needs a recharge. You basically have an autonomous robot running around the house doing your bidding. From the looks of it, this project may help solve another problem from a comment left on the site, a long distance remote controlled boat for water sampling. There are a number of advancements that could come from this hack that could potentially solve many problems that would normally cost a lot more.

@KenThe router power is negligible compared to the power required for the motors. The router takes about 5% of the power when driving. I think there are a number of value-added features that made the project worth doing.

I have been developing a similar robot using an Asus WL-520GU wifi router. I choose the 520GU because it is hard to brick and it has a USB 2.0 port. The USB port has a hub, with 1GB USB flash, and an Arduino plugged into it, and will have two optical mice plugged in for gross position measurement. The router has openwrt and Python installed, and libraries pyserial and pyduino.

I am using an Arduino Duemilanove for the hardware IO, and on that I put http://firmata.org which comes with the arduino build tools as an example (I just built firmata and flashed it – no mods).

Like you, the electronics need a lot less power than the motors. I am using 12V SLA/VRLA batteries… They are heavy but easy to charge and good ones can be got for free from maintenance (UPS/alarms/emergency lights etc). 12V is nice since can get parts from old cars/wreckers and I use an old PSU for developing.

I love what you have done with the Truck and will be using my router+arduino platform to do a few similar things with modded toys. I definitely will be using a horn – great idea!

I have been developing a similar robot using an Asus WL-520GU wifi router. I choose the 520GU because it is hard to brick and it has a USB 2.0 port. The USB port has a hub, with 1GB USB flash, and an Arduino plugged into it, and will have two optical mice plugged in for gross position measurement.I love what you have done with the Truck and will be using my router+arduino platform to do a few similar things with modded toys. I definitely will be using a horn – great idea!